The present invention relates to a configuration for a flange and more particularly for a flange used on a valve, such as a check valve located in a pipe run.
Valves arranged in a pipe run, such as check valves, are well known. A particular type of check valve which is utilized in such an orientation is what is referred to as a wafer style check valve or dual disk check valve such as those disclosed in U.S. Pat. Nos. 4,079,751; 4,257,451; 5,301,709 and 5,711,343.
In these check valves, an outer cylindrical valve body typically mates at each end with a pipe run wherein the ends of the adjoining pipes are provided with flanges and the check valve is captured between the pipe flanges such as shown in FIGS. 2 and 3 of U.S. Pat. No. 4,079,751.
Typically the valve body is also provided with one or more flanges which are sized to engage the sides of the bolts extending between the pipe flanges. The bolts are arranged in a bolt circle and thus the radial inside surface of the bolts define points in a circle of the same diameter as the valve flange.
In a wafer style check valve of the type described above, there are two generally semicircular disks which are mounted to rotate about a hinge pin which passes through the center of the valve body in an axis perpendicular to the pipe axis. For the valve to operate properly, it is important that the valve be installed so that it is closely centered in the pipeline and with the hinge pin oriented very close to the vertical. Centering is necessary so that the disks do not strike the mating pipe. In horizontal pipe applications, gravity tends to force the valve down from center during installation and over time. Vertical orientation is important so that the motion of the disks is not affected unevenly by gravity. Therefore, there is typically only one correct rotational orientation for the valve body.
Different sized pipelines have different sized, but standard, bolt circles for the connecting bolts of the flanges of adjoining pipes. The valve bodies are generally cast with the outside flange of the body having a specific diameter which will mate to one bolt pattern and will support the weight of the valve.
However, there are actually different standards for bolt circles, particularly differences between U.S. bolt patterns and ISO (European) metric bolt patterns. This different diameter of bolt circles of the different standards have required different sized valve bodies and valve flanges to accommodate each of the different bolt circle standards.
It would be an advantage if there were provided an arrangement whereby a single valve body could be utilized to accommodate more than one bolt circle diameter.